In the following circuit the output $$'V'$$ follows an equation of the form
$${{{d^2}V} \over {d{t^2}}} + a.{{dV} \over {dt}} + bV = f\left( t \right).$$
Find $$a,b$$ and $$f(t)$$

$$(a)$$ For the circuit shown in figure

$$(i)$$ Calculate the transfer function $${{{V_0}} \over {{V_i}}}$$
$$(ii)$$ plot the amplitude and phase response as a function for $$R = {R_1}$$

In a common Emitter amplifier, the un bypassed emitter resistance provides

The voltage series feedback in a feedback amplifier leads to

The Circuit shown in figure is excited by the input wave form shown. Sketch the wave form of the output. Assume all the components are ideal

In an $$RC$$- coupled common Emitter amplifier which of the following is true?

For the $$JFET$$ amplifier shown in figure $$\mu = 100,\,{r_d} = 50k\Omega $$
$$(i)$$ Draw the $$AC$$ equivalent circuit
$$(ii)$$ Find the voltage gain of the amp

In the following circuit the $$5$$ $$V$$ zener diode requires a minimum current of $$10$$ $$mA.$$ For obtaining a regulated output of $$5V,$$ the maximum permissible load current $$\left( {{{\rm I}_L}} \right)$$, is ______$$mA$$ and the minimum power rating of zener diode is ________ $$W$$.

In the circuit shown in figure calculate and sketch the wave form of current $$'i'$$ over one period of the i/p voltages. Assume the diodes to be ideal

An ideal op-amp is used to make an inverting amplifier. The two input terminals of the op-amp are at the same potential because

The overall transfer function of the system in Figure, is

For what values of $$'a'$$ does the system shown in figure have a zero steady state error $$\left[ {i.e.,\mathop {Lim}\limits_{t \to \infty } \,\,E\left( t \right)} \right]$$ for a step input?

For what range of $$K$$ is the following system (Figure) asymptotically stable Assume $$K \ge 0$$

Which of the following figure(s) represent valid root loci in the $$s$$ - plane for positive $$K?$$ Assume that the system has transfer function with real coefficient.

A unity feedback system has the open loop transfer function $$G\left( s \right) = {1 \over {\left( {s - 1} \right)\left( {s + 2} \right)\left( {s + 3} \right)}}$$
The Nyquist plot of $$G$$ encircle the origin

If the $$HLT$$ instruction of a $$8085$$ microprocessor is executed,

The time constant of the network shown in Fig. is

The equivalent inductance seen at terminals $$A-B$$ in Fig. is .................... $$H.$$

In the circuit of Fig, the switch $$'S'$$ is closed at $$t=0$$ with $${i_L}\left( 0 \right) = 0$$ and $${V_C}\left( 0 \right) = 0.$$ In the steady state, $${V_C}$$ equals

Using Thevenin equivalent circuit, determine the $$rms$$ value of the voltage across the $$100$$ $$ohm$$ resistor after the switch is closed in the $$3$$ $$-$$ phase circuit shown in Figure.

Resistances in the circuit of fig. are of R $$\Omega$$ each. The switch is initially open. What happens to the lamp's intensity when the switch is closed?

All the resistances in the circuit of Fig. are of 1 $$\Omega$$ each. The value of current 'I' is

A resistance is measured by the voltmeter- ammeter method employing d.c. excitation and a voltmeter of very high resistance connected directly across the unknown resistance. If the voltmeter and ammeter readings are subject to maximum possible errors of $$ \pm 2.4\% $$ and $$ \pm 1.0\% $$ respectively, then the magnitude of the maximum possible percentage error in the value of resistance deduced from the measurement is nearly

An unshielded moving iron voltmeter is used to measure the voltage in an a.c. circuit. If a stray d.c. magnetic field having a component along the axis of the meter coil appears, the meter reading would be

In $$d.c.$$ potentiometer measurements, a second reading is often taken after reversing the polarities of the $$s.c.$$ supply and the unknown voltage, and the average of the two readings is taken. This is, with a view to eliminate the effects of

In a dual slope integrating type digital voltmeter the first integration is carried out for $$10$$ periods of the supply frequency of $$50Hz.$$ If the reference voltage used is $$2V,$$ the total conversion time for an input $$1$$ $$V$$ is _________ sec

The torque angle of a synchronous machine operating from a constant voltage bus, is usually defined as the space angle between

The developed electromagnetic force and or torque in electro $$-$mechanical energy conversion systems act in a direction that tends

Figure depicts the load characteristics of an constant speed. Match the following sets of operating conditions with the given characteristics. Disregard the effects of saliency, saturation and stator resistance.

$$(a)$$ Constant excitation and non-zero leading power-factor
$$(b)$$ Constant excitation and zero power-factor, leading
$$(c)$$ Constant terminal voltage and zero power-factor, leading
$$(d)$$ Constant terminal voltage and non-zero leading power-factor

Neglecting all losses, the developed torque $$(T)$$ of $$d.c.$$ separately excited motor, operating under constant terminal voltage, is related to its output power $$(P)$$ as under

A separately excited $$d.c.$$ motor has an armature resistance of $$0.5$$ $$ohm.$$ It runs off a $$250$$ $$V$$ $$d.c.$$ supply drawing an armature current of $$20$$ $$A$$ at $$1,500$$ $$rpm.$$ The torque developed for an armature current of $$10$$ $$A$$ will be __________ for the same field current.

Two transformers of the same type, using the same grade of iron and conductor materials, are designed to work at the same flux and current densities; but the linear dimensions of one are two times those of the other in all respects. The ratio of $$kVA$$ of the two transformers closely equals

Two transformers of different $$kVA$$ ratings workings in parallel share the load in proportion to their ratings when their

Which of the following equations represents the Gauss's law in a homogeneous isotropic medium?

An electrostatic potential is given by $$\phi=2x\sqrt y$$ volt in the rectangular co-ordinate system. The magnitude of the electric field at x = 1 m,y = 1 m is _________V/m

In the circuit shown in fig, $$L$$ is large and the average value of $$'i'$$ is $$100A.$$ The thyristor is gated in the half cycle of $$'e'$$ at a delay angle $$\alpha $$ equal to ___________.
$$e\left( t \right) = \sqrt 2 .00\,\,\sin \,\,314t$$

The inductance of a power transmission line increases with

The selection of size of conductors for a distributor in a distribution system is governed by

A Buchholz relay is used for

In load flow studies of a power system, the quantities specified at a voltage-controlled bus are ____________and___________

The impulse response of a network is $$h\left( t \right) = 1$$ for $$0 \le t < 1$$ and zero otherwise. Sketch the impulse response of two such networks in cascade, neglecting loading effects.

Match the following transfer functions and impulse responses

Transfer functions
$$\eqalign{ & \left( a \right)\,\,\,\,\,\,\,\,{1 \over {s\left( {s + 1} \right)}} \cr & \left( b \right)\,\,\,\,\,\,\,\,{1 \over {{{\left( {s + 1} \right)}^2}}} \cr & \left( c \right)\,\,\,\,\,\,\,\,{1 \over {s\left( {s + 1} \right) + 1}} \cr & \left( d \right)\,\,\,\,\,\,\,\,{1 \over {{s^2} + 1}} \cr} $$

Impulse Responses